1. Field of the Invention
The present invention relates to a sensor for detecting acceleration in two-dimensions, particularly to a two-dimensional acceleration sensor used for detecting acceleration along two axes, i.e., forward and backward movements and left and right movements of a vehicle. This sensor is adapted for use in a collision device for a driver, or a four wheel steering device, or a device for controlling the height of the vehicle body.
2. Description of the Related Art
Known in the prior art, for example, in Japanese Unexamined Patent Publication No. 62-163972, is a sensor for detecting acceleration along two axes. This prior art is provided with two spherical shells, i.e., an inner shell and an outer shell, and a magnetic fluid is sealingly introduced into a space between the shells. An electro-magnetic means is provided for each axis, and thus the inner shell is floatingly held inside the outer spherical shell. A contact type potentiometer is provided for detecting the position of the inner shell, which varies in accordance with the acceleration of the vehicle.
This prior art suffers from a drawback in that the construction is mechanically complicated, because a contact type sensor is utilized, and the life of the sensor is relatively short.